The primary reason for the deterioration of many food products is the presence of oxygen, and the removal of oxygen from within a container increases the shelf life and thus makes products saleable over a greater period of time while also reducing losses through spoilage. Vacuum deaerators have been commercially available for some time and have been used to lower the oxygen level in liquid products and the like by the simple expedient of subjecting such products to a mechanically induced vacuum. Likewise, at the time of packaging, foodstuffs have been subjected to gas-flushing. For example, nitrogen has long been used as an inerting medium in the production of wine and champagne, and it has also been used to flush or purge empty bottles and to inert the head space in edible oil packaging to improve shelf life and appearance.
Vacuum deaerators are fairly expensive to purchase and are not entirely satisfactory because they do not normally reduce the dissolved oxygen content to a totally acceptable level. Likewise, although head space purging slows deterioration by significantly reducing the amount of oxygen available within the void region of the package with which a reaction can take place, it is limited in the effect which it has upon dissolved oxygen. The use of nitrogen as a sparging material for stripping oxygen from liquids is an effective method of removing dissolved oxygen.